Balisong, also called butterfly knife or fan knife, is a folding pocket knife with two handles counter-rotating around the tang such that, when closed, the blade is concealed within grooves in the handles (From: Wikipedia).

It is sometimes called a Batangas knife, a province in southern Luzon island where the natives were formerly known for manufacturing these handmade and deadly weapons. In the hands of a trained user, the knife blade can be brought to bear quickly using one hand. Manipulations, called “flipping”, are performed for art or amusement.

The balisong is commonly used by Filipinos as a pocket utility knife. It is so popular in the Philippines that an urban legend exists about every Batangueño (native of Batangas) carrying it everywhere he goes as a form of self-defense. There are speculations that the balisong knife was used by Filipinos way back in 800 AD, and was probably employed as an ancient weapon in the Filipino fighting system of eskrima.

The urban legend and nasty reputation of the balisong was further reinforced during World War 2 when US soldiers deployed in the Philippines or the Pacific returned home with handmade balisong knives and tales of horrific duels among so-called ‘savage’ Filipino tribes who used the balisong to redeem lost honor.